Why waste recovery ability when I could utitlize the same energy to add additional weight trianign sessions, which yield a much higher post workout metabolic increase than cardio without causing as much muscle catabolism, and actually stimulate growth. More muscle mass equals a greater metabolism. I stay under 12% body fat year round, do not do hgh, and eat 7000 calories a day.... and have genetics which allow for rapid fat gain, since i was 35% bf when I started training. Weight training and diet are the key.